Missing Gutter Apron When water flows off the edge of your roof, some of it clings to the underside of the shingles and dribbles toward the fascia. If you have gutters but no gutter apron to stop the water, it will wick behind the gutter.
Roof Flashing: Replace Plumbing Vent Flashing | Family Handyman
Outside corners on dormers needs special flashing details to prevent water leaks. This article explains two foolproof methods for making sure that corners shed water and stay dry for the life of the roof.